Look at WMI via the
System.Management namespace[
^] - it provides calls to access all sorts of information about a PC.
But be aware, that simple security like this is easily hacked, and will frequently annoy genuine customers more than it deters pirates. A quick look at any of the torrent sites will show you what I mean...
[edit]I forgot to add this:
How To Get Hardware Information (CPU ID, MainBoard Info, Hard Disk Serial, System Information , ...)[
^] - an article on this very site which shows you how to get loads of info, including the HDD serial number - OriginalGriff[/edit]